Reflective LCD including address lines shaped to reduce parasitic capacitance

• US 6,172,728 B1
• Filed: 02/03/1998
• Issued: 01/09/2001
• Est. Priority Date: 02/07/1997
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Hiraishi, Youichi
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): CHOWDHURY, TARIFUR RASHID
• Application Number:
  US09/017,807
• Time in Patent Office: 1,071 Days
• Field of Search: 349/39, 349/139, 349/145
• US Class Current: 349/139
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 2203/02 reflective

Abstract

A reflective liquid crystal display device according to the present invention includes: a plurality of scanning lines; a plurality of signal lines disposed so as to intersect with the plurality of scanning lines; a plurality of pixel electrodes which also serve as reflective plates and which overlap at least one of the scanning lines and the signal lines via an interlayer insulating film; and a plurality of switching elements for driving the pixel electrodes, each provided in a vicinity of the intersection of the scanning lines and the signal lines. At least one of the scanning lines or the signal lines have at least one of bends, notches, protrusions and holes.

Claims

1. A reflective liquid crystal display device, comprising:

a plurality of address lines including a plurality of scanning lines and a plurality of signal lines the signal lines disposed so as to intersect with corresponding scanning lines;

a plurality of pixel electrodes which also serve as reflective plates and each of which overlaps at least one of the address lines via an interlayer insulating film; and

a plurality of switching elements for driving the pixel electrodes, each switching element provided in a vicinity of an intersection of one of the scanning line and one of the signal lines,

wherein at least one of the address lines has at least one of bends, notches, protrusions and holes formed therein in locations so as to reduce area where pixel electrodes overlap the at least one address line so as to minimize parasitic capacitance.

2. A reflective liquid crystal display device according to claim 1, wherein a parasitic capacitance between each of the scanning lines and each of the pixel electrodes is relatively constant.

3. A reflective liquid crystal display device, comprising:

a plurality of address lines including a plurality of scanning lines and a plurality of signal lines the signal lines disposed so as to intersect with corresponding scanning lines;

a plurality of pixel electrodes which also serve as reflective plates and each of which overlaps at least one of the address lines via an interlayer insulating film;

a plurality of switching elements for driving the pixel electrodes, each switching element provided in a vicinity of an intersection of one of the scanning line and one of the signal lines,

wherein at least one of the address lines has at least one of bends, notches, protrusions, and holes; and

wherein notches of at least one of the address lines are provided in an asymmetric manner with respect to a center line along a length of the at least one address line.

4. A reflective liquid crystal display device, comprising:

a plurality of address lines including a plurality of scanning lines and a plurality of signal lines the signal lines disposed so as to intersect with corresponding scanning lines;

a plurality of pixel electrodes which also serve as reflective plates and each of which overlaps at least one of the address lines via an interlayer insulating film;

a plurality of switching elements for driving the pixel electrodes, each switching element provided in a vicinity of an intersection of one of the scanning line and one of the signal lines,

wherein at least one of the address lines has at least one of bends, notches, protrusions, and holes; and

wherein island-shaped portions made of at least one of the materials used for the scanning lines or the signal lines are provided in areas where the scanning lines or the signal lines do not overlap the pixel electrodes.

5. A reflective liquid crystal display device, comprising:

a plurality of address lines including, a plurality of scanning lines and a plurality of signal lines the signal lines disposed so as to intersect with corresponding scanning lines;

a plurality of pixel electrodes which also serve as reflective plates and each of which overlaps at least one of the address lines via an interlayer insulating film;

a plurality of switching elements for driving the pixel electrodes, each switching element provided in a vicinity of an intersection of one of the scanning line and one of the signal lines,

wherein at least one of the address lines has at least one of bends, notches, protrusions and holes; and

wherein at least one of the scanning lines and the signal lines include a main line and a sub-line which are parallel and connected to each other, and the main line or the sub-line has at least one of bends, notches, protrusions or holes.

6. A method for producing a reflective liquid crystal display device comprising:

a plurality of address lines including a plurality of scanning lines and a plurality of signal lines, the signal lines disposed so as to intersect with corresponding scanning lines;

a plurality of pixel electrodes which also serve as reflective plates and each of which overlaps at least one scanning line or signal line via an interlayer insulating film; and

a plurality of switching elements for driving the pixel electrodes, each switching element provided in a vicinity of an intersection of one of the scanning lines and one of the signal lines,

the method comprising providing at least one of bends, notches, protrusions and holes in at least one of the address lines so as to make the surface of a pixel electrode overlapping the at least one address line uneven, and wherein the at least one of bends, notches, protrusions, and holes are formed in order to reduce area where the pixel electrode overlaps the at least one address line so as to minimize parasitic capacitance.

7. A method for producing a reflective liquid crystal display device according to claim 6, wherein the interlayer insulating film is made of a positive type photosensitive resin.

8. A method for producing a reflective liquid crystal display device comprising a plurality of address lines including a plurality of scanning lines and a plurality of signal lines, the signal lines disposed so as to intersect with corresponding scanning lines;

a plurality of pixel electrodes which also serve as reflective plates and each of which overlaps at least one scanning line or signal line via an interlayer insulating film; and

a plurality of switching elements for driving the pixel electrodes, each switching element provided in a vicinity of an intersection of one of the scanning lines and one of the signal lines,

the method comprising providing at least one of bends, notches, protrusions and holes in at least one of the address lines so as to make the surface of a pixel electrode overlapping the at least one address line uneven, and wherein surfaces of the pixel electrodes are made uneven by the interlayer insulating film which is exposed to light while using the scanning lines and the signal lines as masks.

9. A method for producing, a reflective liquid crystal display device comprising a plurality of address lines including a plurality of scanning lines and a plurality of signal lines, the signal lines disposed so as to intersect with corresponding scanning lines;

a plurality of pixel electrodes which also serve as reflective plates and each of which overlaps at least one scanning line or signal line via an interlayer insulating film; and

a plurality of switching elements for driving the pixel electrodes, each switching element provided in a vicinity of an intersection of one of the scanning lines and one of the signal lines,

the method comprising, providing at least one of bends, notches, protrusions and holes in at least one of the address lines so as to make the surface of a pixel electrode overlapping the at least one address line uneven, and wherein island-shaped portions made of at least one of the materials used for the scanning lines or the signal lines are provided in areas where the scanning lines or the signal lines do not overlap the pixel electrodes.

10. A method for producing a reflective liquid crystal display device comprising a plurality of address lines including a plurality of scanning lines and a plurality of signal lines, the signal lines disposed so as to intersect with corresponding scanning lines;

a plurality of pixel electrodes which also serve as reflective plates and each of which overlaps at least one scanning line or signal line via an interlayer insulating film; and

a plurality of switching elements for driving the pixel electrodes, each switching element provided in a vicinity of an intersection of one of the scanning lines and one of the signal lines, and wherein;

the method comprises reducing a surface area of at least one address line while not reducing a width of said address line at a portion thereof, in a manner so as to reduce an area where pixel electrodes overlap the at least one address line in order to reduce or minimize parasitic capacitance.